I have a 120V/15A pressure washer that's tripping the breaker and its own built-in-to-the-cord GFCI under certain conditions.
All of the available outdoor receptacles are on a single 15A circuit, chained off a single GFCI receptacle. The breaker is a plain (not GFCI) breaker.
When plugged directly into the GFCI receptacle (two GFCI's right on top of each other), the pressure washer works fine. But when plugged into either of the other receptacles chained from it, or into a (suitably rated) extension cord from the GFCI outlet, it trips the breaker and the GFCI after about 5-10 seconds of use.
In case the total wire length was just causing a loss that made the borderline current capacity insufficient, I also tried running the extension from a 20A circuit inside (also GFCI protected; I don't have any 20A circuits that aren't), but that also tripped. This leads me to believe it might be something about having 2 GFCI's chained with some distance between them, possibly causing spurious trips. Is there some phenomenon by which this happens, and if so, is there a standard fix?
How do I solve this in a way that's safe and code-compliant?